Method and apparatus for pumping a volatile liquid



June L3, 1952 Filed July 18, 1941 l 2 if i 1 I w. F. MEslNGl-:R 2,598,816

METHOD AND APPARATUS FOR PUMPING A VOLATILE LIQUID 3 Sheets-Sheet 2 243 l :mili @j ,272 275 'j i 271 y 24j 246 ya 23% 245 25'# "lvul .Y 2 3 ATTORN EYS June 3, 1952 W F, MES|NGER 2,598,816

METHOD ND APPARATUS FOR PUMPING A VOLTILE LIQUI D Filed July 18, 1941 5 Sheets-5h66? l INVENTOR l ATTORNE June 3, 1952 w. F. MESINGER 2,598,816

METHOD AND APPARATUS Foa PUMPING A VOLAND-D LIQUID Filed July 18, 1941 5 Sheets-Shee 3 A -EEEI N M m D N D I l INVENTOR TORNE Patented June 3, 1952 UNITED STATES PATENT OFFICE METHOD AND APPARATUS FOR PUMPING A VDLATILE LIQUID' William F. Mesinger, Mount Vernon, N. Y., assignor, by mesne assignments, to Union Carbide and Carbon Corporation, a corporation of New York Application July 1s, 1941', serial No. 402,891

s4 claims. (o1. 10s-153) This invention relates to a method and apparatus for pumping a volatile liquid, and particularly to the pumping of a liquid which has its boiling point temperature at atmospheric pressure materially below 273 such as liquid oxygen.

The invention has for its object generally the provision of a combination of improved pumping steps, together with suitable apparatus for effecting the same, whereby a highly volatile liquid may be positively pumped by a reciprocating type pump, particularly one having a plunger, against relatively high heads of pressure.

More specically, the invention has yfor its object the provision of a novel cycle of pumping steps whereby the material in the liquid phase may be positively displaced and any material vaporized in the `pump is readily removed, together with suitable plunger pumping apparatus and auxiliaries therefor, whereby the several pumping steps of the invention are carried out.

Another object of the invention is to provide an larrangement of apparatus for pumping a liq' ueed gas of the character indicated with a plunger type pump having adequate clearances and liquid inlets and outlets so arranged that displacement of the liquid by opposite movements of the piston and liquid is effected. In addition to the peripheral clearance about the plunger characteristic of plunger type pumps, there will necessarily be a small clearance at the end of the discharge stroke.

Another object of the invention is to provide a pump construction having the clearances consistent with said opposite movements, with means for compensating for such clearances and for nearly Acompletely offsetting the inefficiency otherwise incident to the presence of vaporized gas material that would tend to occupy such clearances.

Another object is to provide a pump of the character indicated with a plunger arranged for conducting relatively little heat from the outside atmosphere to the liquid being pumped.

Another object is to provide a plunger type pump with an improved packing that is heated so as to operate under substantially optimum packing conditions when pumping a relatively cold liquid such as liquid oxygen.

Another object is to provide a plunger type pump with an auxiliary gas pump for removing any gas phase generated internally that 'would otherwise tend to reduce the pumping eiciency of the pump, or permit the same to become gasbound.

Still another object of the invention is to provide a suitable arrangement for positively operating and timing the valves in a plunger type pump whereby the inflow of liquid phase material is properly controlled and coordinated with the movement of gas phase material in the interior of the pump during the pumping cycle.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the apparatus embodying features of construction, combinations of elements and arrangement of parts which are adapted to effect such steps, all as exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:

Fig. 1 is a view, mainly in side elevation, showing schematically a pump arranged for pumping a volatile liquid in accordance with the invention;

Fig. 2 is Aan enlarged vertical sectional view of the pump shown in Fig. 1, parts being shown in elevation, constructed in accordance with the invention;

Fig. 3 is a sectional view, taken on the line 3-3 in Fig. 2;

Fig. 4 is Yan enlarged sectional view showing details of a valve device employed in the presentinvention; and

Fig. 5 is a fragmentaryview, partly in section and partly in elevation, showinga modification.

In the practice of the present invention two major steps are employed in association with a pump having a plunger provided with a clearance space thereabout. The rst step operates to draw liquid from a source of supply into the pump chamber; the second effects the discharge of liquid by positive displacement thereof, the effects of gas binding being minimized by providing for a counter-movement of liquid and piston upon the discharge.

.When the liquid entering the pump is of only slightly lower temperature than the plunger so that heat exchange and vaporization result and suction by the plunger may not be depended upon to `draw in a charge of liquid, a suitable pressure.. feed is provided, such as may be had by a grav- -4 ityfeed of the liquid to the Vpump cylinder, as

shown, to minimize the vaporization.- The gas 3l thus generated is positively removed subsequently by the employment of an auxiliary gas pump, such removal being accomplished during the short interval transpiring while the suction stroke t is being completed. The pump cylinder is at the same time: cooled; by permitting'ebullition of lio-- uid in a surrounding. jacket. Heat is thus re-v moved from the parts of the pump while gas isV at the same time generated.

Upon the beginning of the discharge stroke. pressure begins to rise in the pump chamber of the pump untila value is rattained sufci'ent `to open a discharge valve that is normallybiased.

closed. rlEhis event may be hastenediby mornene.` tarily admitting gas at a relatively highV pressure-` into the clearance space at the beginning of the discharge stroke, which operatesto offset the eect of such clearance. YLiquid is thus positively discharged at a relatively high pressure during Ythe balance of the discharge stroke. Y

A. pumping apparatusv constructed to, carry out;th'e;steps.ofi the; invention consistsofa pumpingk chamberv or cylinder in whichY reciprocates 'a'. diametrically smaller plunger whichv is. pref-- erably hollow to reduce the massA of metal` and'` filled.A with suitable insulation in order to. profvide support' for its. walls. Connectedv to thev cylinder are liquid supply andL discharge. conduits having suitablevalves for controlling the inlet to and' outletV .from the cylinder.V Preferably three mechanically operated suction. stroke` valves are. provided, one. at the bottom andltwo at or near the upper'portion. of the cylinder; Vthe valve at the bottom being. arranged. toallow liquid to run into the cylinder while the upper two.` vent any gas back to the source of4 liquid supply, such as a liquid oxygen storage container. A suitable auxiliary or gas pump, which may be of a .bellows type, is inserted in the'vapor line tov achieve the positive removal. of 'the `gas from. the pump cylinder during the,

suction stroke and put it back at the beginning' v momentarily to receive gas material from'. the

cylinder at the end ofthe discharge stroke in order to reduce the pressure of the gas remaining in the clearance space before a suctionl stroke begins and is again opened for a moment to discharge back the received gas material'under'pressure to the cylinder.V Thek open.- ing at the beginning. of the discharge stroke is' seen-toy minimizethe. effect of the plunger clearance space andy further to supercharge the'V pump. cylinder.. A Yfore-chamber is provided andA maintained at a relatively low pressure and preferably surrounds the pump cylinder and is.

kept full of 'liquid drawn from the. storage cony tainerin order to assist in keeping the Vpump cylinder cold. The discharge conduit is preferably disposed. in heat conducting relation. with thefpump'cylinder at a point betweenthe lower portion anda plungerpacking sleeve, in orderl to keepitco'ol,v thus preventing excessive transfer of heatfrom the packing end toward'the pump cylinder; The-.top portion ofthe packing` sleeve is1 also` advantageously provided with a suitable luStration) heating means, such as an electric heater, in order that it may be maintained at a temperature consistent with good packing operation.

Referring now to the drawing, and particularly to Fig. 1, a storage container is shown at I0, which is, of az character.' adapted tof'hold a supply ofthe liqueed gasto be, pumped to receiving or consuming apparatus (not shown in the drawing in the interests of clearness of il- From the bottom of the container Il). a; liquid supply' line II is diagrammatically indicated as leading to the inlet of a plunger pump; here denoted. generally by I5. Such pump-nasa casing' |50 and is provided with a gas phase equalzing connection I2 leading to the gas space` ofthe container ID. A liquid phase: dischargeV connection I3 leads from the outlet of the pump; container I0 being shown as' also having a filling connection I4. y

The pump I5 may have any convenient location with respect to the containerr .ID but. is here shown, byway of illustration, IruziuntedV witnitscasing onV a. floor or ground and having itsiinletatfav level a little. below the bottom of thev container, in order to provide the desiredpressure at the inlet.

Details of' an exemplary construction for by providing an insulating. filling forfth'e. plunger, which is both. mechanicallyv strong and aA relatively poor conductor ofheat,. the'metal wall' oflr the plunger 28l can be madev quitev thin andi the heat: storageY capacityV and conductivity of.

Vthe plunger may thenVV be correspondingly rex-A duced The heat-storage capacity is'an appreciable factor vbecause the plunger absorbs-some heat in. its. upper position, and the. smaller `its heat capacity the smaller will be the' amount. of'heat carried' to the pump cylinder whenv theplunger is in the lower position. Such plunger' is arranged to passf downwardly into a. pump chamber 210 through' asleeve 21 which has a.-

packing.l 22 associated therewith. Thepump Ychamber ZI-Il is formed asv the bore. of' a pump4 cylinder whichy may be provided either as a single member, or as a plurality of Yassociated members. A plurality of members is here shown in the drawing, by'way of example; since it' facilitates manufacture.

Accordingly, anupper member 2-31 isprovided which has its upper portion reducedf to provide sleeve 2`.I, the exterior of which hasV a thread'.v at 211 by which nuts and other parts arel held inV place, as hereinafter explained. To member 23= is# attached" a lower member 24 which continues theI bore 2-IfIly comprising the portion ofchamber inr whichthe-"plunger 20 works. Thisllower portion may .be appropriately referredto asthe workingV barrel portion; The diameter of theV boreis made suciently greater than that offthe plunger to provideV the* desired clearance space about the plunger. This clearance space may be varied somewhat depending uponY the inner diameter ofthe cylinder and the speed of operation of the plunger. In general it should be* small but suiiicient to permit the counter-flowy of'tlie` liquid' past the plunger during the discharge-stroke without subjecting the liquid to an` excessiveV speed of now such as to causel fric-- tional heating. The lower end of member 24 is closed by a base member 25 which may be threadedly attached to member 24, and is preferably counterbored, as shown at 250, and has a plurality of passages, as at 25| and 252, leading thereinto. The base member 25, which thus serves to support the members 23 and 24, preferably has a central boss 25' or upstanding portion formed about the counterbore or depression 250 and serves as a support for a Wall 26 of a jacket chamber 26|); such wall being cylindrical and of greater diameter than that of the inner or lower member 24. By this means, wall 26 is held in spaced relation to the member 24 between the base member 25 and the upper member 23; the latter preferably having a depending boss 23 of the same diameter' as boss 25' and of a character adapted to be received in the upper end of wall 26. By this means the intervening space is seen to be annularly formed and adapted for cooling the pump chamber 2|0. The base member 25 thus serves to close at the bottom not only the pump chamber but also the jacket chamber. The jacket chamber 260 is made to serve as a fore-chamber to the pump chamber 2|0 by providing thel jacket wall 26 with a nipple 2|| at one side, to which the liquid inlet connection is attached; there being also another y passage 2| 2 in fbase member 25 which connects chamber 260 to passage 252.

A valve is provided in these connections to control the inlet of liquid to the pump chamber 2|0.

Accordingly, the inner end of passage 252 is re.

duced as at 253 to provide a shoulder 254 upon which seats a valve 255 that is on a stem 256. 'Ihis latter is slidably mounted in a sleeve 251 that has a packing 258 retained by a gland or nut 259; the sleeve being shown as having threaded engagement with the -outer end of passage 252. The stem 256 projects to the exterior of the pump and has actuating force applied as hereinafter described. An enlarged view of this construction is shown in Fig. 4, where' it is seen that the stem 256 has a sleeve coupling 254 connecting it to a cam follower 265 which is actuated by a cam 265. By such arrangement, it is seen that when the .opening of the valve 255 is synchronized with the upward or suction stroke of plunger 20, liquid ilows into the pump chamber v2|l| from the storage container |0.

The jacket or fore-chamber 260 is preferably vented to the gas space of the storage container, in order that the liquid therein may be in pressure equilibrium with the contents of the storage container and moved under the influence of a uniform force, here the force of gravity, rst into the fore-chamber 260 and from the forechamber into the pump chamber 2| 0 when a suction stroke takes place. To accomplish such venting, the lower portion of member 23 is provided with passages 23| and 232 leading from the upper part of chamber 260 to a point at which connection |2, that communicates with the container gas space, is attached. The inlet end of passage 23| is preferably provided with a float valve 235 in a cage 233, in order to prevent the entry of liquid, such cage having gas'passages at 234. This valve is of a suitable construction and relative weight such that it will normally float on the liquid, but will have sufciently greater weight than an equal volume of the gas, such that, when suspended in gas only, it will overcome a substantial amount'of differentialigas pressure and drop down. f

Venting passage 232 is traversed by a passage' 245 to which is attached a metallic bellows 248" anchored in a removable cap or nut 249 of th-e sleeve. Valve 245 seats on a valve opening provided at the juncture of the upper port'ion'ofr passage 236 with that of 232. t

When valve 245 is open, it establishes com' munication through the upper portion of passage 236 between passages 23|-232 and additional gas escape passages 24|- 242 which communicate with pump chamber 2|0 at a point a little below the upper end of the stroke of plunger 20. Passage 24| is reduced and provides a shoulder at its juncture with passage 242 upon which seats a valve 245 which is similar but preferably of enlarged form relative to that at 245. Valve 245 is shown as of the packless type and has an actuating stem 246' in a sleeve closed by a cap or nut 249.

. Passage 242 also has communicating with it Va passage 243 leading to a chamber 244 in which works a piston for the gas pump which is' arranged to be actuated in synchronism withuthe strokes of plunger 20.

The passages 23|232, 24|-242, together with that at 243 and chamber .244, are preferably provided as .bores in a portion of member 23 which is enlarged to accommodate the same, such enlargement being shown at 23X; a crosssection of the same along a broken line appearing in Fig. 3. Here it is seen that at a point a little above the inner end of passage 24| another set of passages is provided. This other set comprises horizontal passage 21| that is connected by vertical passage 212 to a third passage 213 which communicates with discharge connection |3, this latter including a coiled portion |23 that is disposed about the neck of upper portion 23 below itsV threads 2|'. At the juncture of passages 212 and 213 is a Vvalve seat 214 on `which seats by gravity a valve 215; the enlargement 23x pref-- erably being formed with vextensions of these passages which are closed with suitable plugs, in

order that access may be readily had thereto forv stricted, an annular recess 218 is cut in the wall'v of the pump chamber, thereby giving relatively free access from all parts of the liquid at this height into the passage 21|.

The passage 25| in the base member leads to a gas receiver or vessel 220 that has a connection 22| leading into an enlarged horizontal portion 222 which joins passage 25| and provides a Yshoulder on which a valve 255 seats. Valve 255 is preferably similar to that at 255 and has an actuating vstem 256' sliding ina sleeve 251' that engazges threadedly with the outer end of passage 22 The gas pump chamber 244 may have any convenient construction. The arrangement for suchv here shown comprises a recess in the upper facev bellows being anchored 'at its upper end to the interior of cap 28, the lower ed'of the bellows Rod 28 is arranged to actuate a`bellws 30 which serves as a piston in chamber 24,4, `the phase winnie being.' closedby' the' rod-j atteler-ring, means emfonremovingf gas. from the-pump cham- Shy-'snella arrangement the? gas pump is Accordingly, iti isa desired. that.. rod; .291 shall. be ac.-

tuated in synchronism with plunger- 201 but not in 4Ill'he passages` Mila-242 which communicate wftlzr. passage 232, provideV means for-venting the gast Withdrawnv by the gas pump by Way fof, pas.- sage 236, valvei 245 andv` connection l2;- the valve 2&5 being, controlled byva cam, as hereinafterde- 1 scribe@ such l.ca-m. being, aV pari',v ofthe train ofr mechanism which also :aromatesl valves 245', 2.55,

bellowsz DI.. Thepacking' spacein sleeve 2i' is here provided counterboringthe bore ZHl; av desired distance tbfomr. acylindri'cal chamber into: which packing, in the form of a pluralityoi packing rings l 22,. is'introduced and held in place by a gland The packing ableeliquisuch. as. tricresyl Yphosphate or the like. the threaded upper end of sleeve 2'l are alsd'disposed lock nuts 34between which and the ingrasia-chat;of.l insulating-material and' an electrical resistancecoil 35 embedded. therein. Such heateniscenergizedrwhen desired from a suitable source of:Y current,n fur example, from bus-bars,

l aashownat 311;. v

Inrorder to; actnatethe plunger the rod 29 of the gas: pump, andv the several .valvesY in the proper sequence to. carry out the stepsof'the invention, VprimeY movingmeans properly cor-V related and mechanically coupled. for actuating these-aparts; are provided. While any suitable.A

3o' nut,3:3; is preierably'disposedfaheaterlS-5 comprisprime movers,V of'. course,` may be employed. that'Vv the drawing byway of example compriseszasinglefelectricmotor M (see'Fig. I). Such motor, is connected'to drive a gear or pulleyv 40' v V12.A connected.l toactuate one end of a Walking beam: 4'3.' This latteris:V fulcrumed or pivoa-lly mounted on the upper portion ofi casing |fzby a rocking linleM'; the otherfend Il5 ofithewalking y beam being pivotally connected to plunger 20;

Pulley 40is arranged to drive or mesh with a gear V5l)V on a camshaft 5I that is so) geared asf to rotatewith a suitable speed relative-to the pulley 40.., ,Shai't5l passes into'l and is journaledincasing |58,V and is geared to drive another' cam shaft4 5,2 that isverticallyfdisposed andalsojournaled incasing 150. Shaft.5l. carries a cam: 5,3.Whichhas 8i. Y face, in; order; to actuateVV positively both direc-,etionsV the gas pump through a followinglever 66 pivotally mounted on thecasing |50 With-one arm. connected to rod 29", while the other Worksin the cam groove.

In. operation, the pump' of the present invention is setV in motion bystarting the motorMand admitting liquid-phase, for example;y by opening thecontrolling valve in conduit H. 'I'heY packing-l heater 35 is also: preferably started at the same time. Y Y

From. the `arrangement described, it is'seen. that, when thefpulley 1li-*3: rotates, the plunger' 29; iskk reciprocated through the linkage -4fl-42-4f3f and the cam'shafts 5i and 552' rotated'` together with` their severalcams which. arey ofcourse, adjusted. to have the desired phase relationship. When plunger 20.' ismoved by: pulley 4D from thebottom: of chamber 210' toV the top. a suctionY strolre takes place.

At thel beginning of thesuctionv stroke, the valves. 245', 245' andI 255 are opened. Are-expansion of the gas remaining in the pump chamber'2l'0 is thus allowed to take placethrough valves 245 and 245 backtothe gas space of the liquidl `storage container. At the` same time, the piston B of the gas pump is pulled up therebyA drawing into the cylinder 21- a charge of gas. This collapses the belloWsS and materially con.- tributes to the positive displacement of the gas' from the pump chamber 2 I0,.depending upon the relative capacity ofthe. pump chamber 2|0 to that ofthe gas pump. It is seen, in consequence.. that 35 liquid rises substantially to the opening of' passage 2M when the suction stroke is completed. The plunger 2'0 dwells at the upper end of itsY stroke for a short period duetoY the crank movement through Vdead center positionv andy during this dwell period supercharging takes. place. Valves .255 and 2-4-5 now close, and the bellows' 35- of the gas pump is quickly and full distended. forcing thefgascharge therein into the clearancel space about plunger 20 inK the upperv portion of pumpchamberZ-I This gives an almost instantaneous supercliargingv eiiect. After the bellows: 30` hasbecome fully distended,v and with plunger 2= still near the top of its stroke, valve 245 is;

closed.. At this same instant valve 255 is` opened to admit more gas from the vessel or chamber 220;. Where it has been retained under la. higher pressure, intoVV the pump chamber 210 below plunger 20, the gas passing into the liquidv which partly condenses it. This valve 255' remains. open. for only a short period of time and closes at or before the instant When the plunger con-A tacts theliquid in chamber 210. Thus the gas pump furnishes the lirst stage of supercharging, and vessel 220:through valve 255' furnishes the secondstage. As plunger 25 contacts the` Y liquid in chamber-219, some gas is generated: and

aprotrusionorother formation on itsofacefor en- `gagi'ng with a follower 55 that is on the stem 256' ofvalve. 2.55.' for actuating the same. Shaft52 carries. cam 2.65 atits lower end inside the. fol,-

lower 266. andv has three additional cams, namely,

those actuating followers at 46. and 56. and cam. 55,. Follower Mhas a linkd'l, connecting it to one-V with; a. sinuous groove. cut its cylindrical; sur

the parts are cooled. Compression of the gas Y ensues, Yand liquid rises and finds exit past valve 215. As plunger 20 reaches the bottom of chamber I-l)V and the discharge stroke is completed, valver2-.55 opens again momentarily andl allowsin part a re-expansion of the residual gas in chamber 2H). to drive liquid and gas from thev clearance space intovessel 22,0, after which valve 255 closes again.r The material thus accumulated. in vessel 220 under pressure is, of course;V used inthe next cycle to supercharge the chamber ZIO, as described.. above. YAt. this point, a new cycle begins Withthe rising of. plunger 20 andthe simultaneousfopening of valves 255, 245, and 24,5',

force. and type as valves 2185 Aand 255.

The movementsof the plunger 2B, the rod v2 9, and the valves are seen to be eiected in proper s equence by the crank and gearing actuated by the motor M.

In the modified form of the invention shown in Fig. 5, the bellows type gas pump is dispensed with, also the connection of the gas escape passages back to the gas space of the storage container. In the modified form, a rotary type of gas pump is employed and auxiliary gas receivers are associated therewith in order to receive and store gas phase for release under pressure to effect the iirst stage of supercharging.

Here a passage 28| is arranged to lead oi gas into a passage 232 whichhas a third passage 283 leading -thereinto and controlled by a valve 245 which functions as does that at 245 in Fig. 2. At the junction of passages 28| and '282 there is a shoulder upon which seats a valve 285 that is arranged -to .be cam actuated in substantially the same manner as, and is similar in construction to, that at 255. Hence it is shown having its stem passed to-the exterior through a threaded sleeve 287. Escape of gas from passage 282 isprovided by way of a connection 288 which communicates at its inner end with passage 282 and leads to a receiver or vessel 255B and to a rotary type gas pump 3dB. Gas pump 36|) is advantageously driven by means of an independent prime mover, such as motor M, the receiver 29|) being connected to the line .at 288 by a branch connection.

To provide for `introduction of the withdrawn gas when under pressure, a passage 29| is arranged to lead into plunger bore 2|!) at a point substantially opposite passage 21| whichtleads ,oi thel discharged liquid. Passage 29| leads from .a second passage v292 that Ahas a third passage 293 leading thereinto from a connection 299-leading from the discharge'side of pump 350.: At the juncture of passage 29| with passage 292` is another shoulderwhich provides a seat for a valve 285 that has a stem in a sleeve 297 passing to the outside of the pump fol1 receiving actuating Valve 295 is preferably of the same form .Gas pump 3D0 and its motor Mare arranged for continuous performance and another receiver or-vessel 3|() is provided on the vdischarge side of the pump and floatingly connected to the connection 239, as indicated.

. In operation, this second form of the invention is seen to have valves which are operated in proper sequence by cams, as in the first modication. The gas entering connection 288, when either valve 245" or 285 is open, first passes into y receiver 290, as the volume of such gas is generally greater than the capacity of pump 300 ,tov receive momentarily. The pump 300,-by its continued operation, gradually draws out the gas from receiver 290 when valves 245 and 285 are vclosed and compresses it and discharges it at a relatively` high pressure into the connection 299. The receiver 3 |0 receives andstores this gas until the valve 295opens When a charge of gas for supercharging purposes is admitted therefrom into chamber 2 0;; ;It is contemplated thatthis charge tion which are capable of utilization to advantage Without incorporation therein of either supercharging means.

Since certain changes in carrying out theabove method and in the constructions set'forth, which embody the invention, may be made without decircumstances or conditions of operation one or 'the other ofthese two. means may be omitted.

features of constructionv and principles ofoperaparting Yfrom its scope, it is intended Athat all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

Having described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. Apparatus for pumping a volatile liquid having a boiling point temperature materially less than 273 K. at atmospheric pressure, comprising the combination with a device for supplying liquid to be pumpedv having therein spaces for both gas and liquid, of a pump having a pump chamber in communication respectively with said gas and liquid spaces, valve means for closing said communication, a liquid discharge for said pump chamber, a plunger arranged to workin said pump chamber, the latter being provided with a desired clearance and said plunger being adapted to displace liquid through said discharge, means for supercharging the clearance space in said pump chamber by the addition of material being pumped at a pressure higher than the normal inlet pressure, and correlated means .for actuating said plunger, said valve means and said supercharging means.

2. Apparatus vfor pumping a volatile liquid having'a boiling point temperature materially less than 273 K. at atmospheric pressure, comprising the' combination with a container for supplying liquid tobe pumped, of a pump having a pump chamber `and a fore chamber surrounding the pump chamber connected to said container and arranged to maintain therein a supply of the material being pumped, valve means for controlling the admission of liquid to said pump chamber from said fore chamber, a liquid discharge for said pump chamber, a plunger arranged to Work in said-pump chamber, the latter being provided with adesired clearance and said plunger being .adapted to displace liquid through said dischargeby the counter-movement of liquid and plungenand correlated means for actuating said plunger and said valve means.

3. Apparatus for pumping a volatile liquid having a boiling point temperature materially less than 273 K. at atmospheric pressure, comprising the combination of a pump chamber, valve means for controlling the admissionof liquid to said pump chamber, a'liquid discharge for said pumpchamber, a plunger arranged towork in said pump. chamber, the latter being provided with a'desired clearance and said plunger being adapted to displace liquid through said discharge, means for supercharging the clearance space in said pump chamber by the addition of material being lpumped at a pressure above the normal inletpressure and provided with valve means controlling communication with said pump chamber, and correlated means for actuating said plunger and said last mentioned valve means.

4. Apparatus for pumping a volatile liquid having a boiling point temperature materiallyless than 273 K. .at atmospheric pressure, comprising the combination with a container for supplying liquid to be pumped, of a pump having a pumpchamber and a surrounding fore chamber connected to said container and to `said pump chamber,V valve means for controlling" the admission ofliquidfto said :pump Vchamber :through (said fore chamber, a second valve means forlcontrolling the venting of gas from said pump-chamber. a liquid vdischarge Vfor said pumpy chamber, va'rp'lungeri arranged "to work in said pump chamfber, the latter .being provided with a desired clearance and said .plungernbeing adapted to dis- `.place liquid through said discharge by the 'counter-movement of 'liquid and plunger, means .-'for ysupercharging the clearance .space in Vsaid pump chamber, a third valve means control- 'ling .communication .betweenl .said supercharging means and Asaid vpump chamber, 'and means for actuating said plunger and all .of .said Valve means. Y

'55. Apparatus 'forpumpinga volatile liquid lhav- -ing a vboiling point 'temperaturematerially .less

:than 2.73 K. .atiatmospheric pressure, `compris- 'ing'thecombination .of a pump having a pump chamber, Lvalve means for @controlling vthe tadmission of liquid `to fsaid'pump chamber, asecond Y:valve vmeans kfor :controlling the venting .of .gas i romgsaid pump .cham-ber, a liquid Idischarge for .-said pump chamber, a :plunger :arranged -t work insaidpump chamber, V.the Y:latter being provided with .a desired clearancey :and said plunger being adapted to .displace :liquid through .said discharge, packing for said plunger, means for supercharging 'the clearancespace-in said pump chamber, a. third Yvalve'meanscontrolling communication between fsaid'supercharging means and'saidgpump chamber, and correlated means .for actuating .said plunger and. :said .second .and valve zmeans.

f6. Apparatus `for .pumping avolatileifliquid, having .a :boiling point :temperature materially -less than 213 K. at :atmospheric pressure, comprisfing-'fa pump chamber, .valvemeans for controly :ling :the :admission :of liquid l.to .said pump. charn- 1ber, '-a second valve means :for .controlling the `ventingfo gas from Vsaid pump chamber, .af-liquid 'discharge :for said pump chamber, .a .plunger-.far-

.chamber with gas. vat 'elevated ipressure. when suction stroke is completed, .a gas v.pump-for 'ele- `-vating .the .pressure :of said gas, a :pack-ing l:for :sa-idfplunger, .means for :heating saidpacking, and

correlated' means for .actuating saidgplunger, allv :offsaid .valve .means and'said .gaspump 7;. Apparatusior pumpingavolatile liquidhav `fing a boiling point temperature materially less `than '273 K. iatzatmospheric pressure. compris- ;ing axpump chamber having suitable 'intakey vand :discharge conduits.a-reciprocable pumping ele- .ment .operable in said chamber` having vva porl ltion extending 'through one end of. Vsaid v.chamflater.V packing means -for Ysaid portion, heating :means associated. with said packingY means fto maintain ,itwithn la desired operating tempera- :ture range, and Vmea-ns .for leading Athe :discharge zfrom said chamber in as-heat .exchangmgurelation with. the pump between said heating means andthe pump chamber.

8. vApparadzus lfor pumping a volatileiliquidhav- -ing.-;a.:boilingxpoint temperature materially less `than 217-3 K. at .atmospheric pressure, compris.-

ing 4.the combination, ofya :pump having .a ,pump

chamber, a '.liquid discharge for1saidchamber, :a `plunger-:arranged .to .Work Ain saidv pump :cham- `-ber and havinga desired clearanceandarranged to Vreciprocate in .said `pump lchamber .and effect the dischargeY of liquid, valve means controlling the `communication .between .said pump chamber and the source of supply, said pump parts being adapted to be cooled by `theevaporation of a vportion of said liquid when introduced into said pump chamberga gas pump for .positively removing said vapors during the suction stroke of said plunger, a second'val-ve-meanscontrolling the Acommunication lbetween said `gas pumpv and said pump chamber, and prime moving means connected to actuate said plunger and Vsaid .second valve means in synchronism and'in desired phases.

9. Apparatus for .transferring volatile liquids comprising a reciprocating type pump, inlet and discharge v connections therefor, -a closed-chamber independently connected -to the interior vof `said pump, valve means for controlling each of said connections, and means foreoperating said valve means in timed relation with the voperation .of saidpump to permit passage of material into Vsaid chamber lfrom said .'pump'and vfrom Asaid chamber into said pump ati-predetermined times in the cycle.

10. Apparatus for pumping a volatile liquid having a lboiling point temperature materially less than 273 K. at atmospheric pressure, comprising a pump chamber, a reciprocable plunger operable through an opening in one vend of said chamber, the latter being constructed to provide an vappreciable clearance between |said Vplunger and -the inner Walls of said' chamber, a valveLcon- 'trolled liquidv inlet at'the end of Asaid chamber opposite to said opening, a valve controlled passage for liquid discharge, and a valve controlled passage for gas, both said passages'having vtheir communication with said chamber spaced a considerable distance from -said' inlet `tov'vard the 'end having said plunger opening.

l1l'. Apparatus for pumping a volatile liquidV vhaving a boiling point temperature materially less lthan 273 K. at atmospheric pressure com-- -prising the combination of a pump chamber, a reciprocable plunger yoperableV through an -opening in one end of said chamber,-a valve controlled liquid inlet near vvthe end of said chamber-opposite `to said opening, `a valve controlled 'passage for` liquiddiScharge, uid venting -means spaced a considerable distance fromA said inlet i'toward the end having Vsaid plunger opening, vand' pack- #ing means for the portion of the plunger passing through said opening; at least that --portion o'f vthe plunger ycoming into contact `with the.

-volatile liquid beinghollow and hav-ing a rela- `tivelyithin external .wall of a metal having a'relati-vely'flowheat conductivity.

212; Pumping apparatus 4according vto claimv 11 which .theholl'ow of said plungeris :a iwall supporting. `material .having .-'a :lower Iheat `conductivity Vthan :said metal.

113. 4Apparatus for .pumping .a volatile fliqueed .gas material .having- .a boiling .point temperature 'materially less than. .2F73o4 K. :at atmosphericipressure, 'comprising a sourceofsupply ofsuch-liquid, -a 'pump chamber, a Areciprocatory element soplerable in ysaid chamber, means :for introducing liquid I-irom said sourceintosaid.chamber during the suction stroke, land 'means :for injecting van additional lquantity of said gas material Iinto` said chamber preliminary lto `'the discharge .stroke .-at a. pressure higher than that afforded Pby: said source tosuperchargethepump.. l.

14, Apparatus iorr .pumping .za Vvolatile. liquid .lha-ving va boilingpoint tmperaturematerially-:less than :273 K. .atlatmospheric pressure, compris'.-

asfissia ing 'apumping chamber provided with a reciprocatory. element, means for operating said element, inletand outlet valves for said chamber, 'asource of supply of such liquid connected `to `gas material having a boiling'point'temperature materially less than 273 K. at atmospheric pressure, comprising a source of supply of such liquid, a pump chamber, a reciprocatory element operable in said chamber, means for introducing liquid from said source into said chamber during the suction stroke, and auxiliary means operative to remove gas material from said chamber afterv the pump discharge stroke and to jre- A.introduce it into said chamber-prior to the next discharge stroke to supplement the charge from said ysource and at a higher pressure thanthat -afforded by said source to supercharge the pump.

16. Apparatus for delivering under pressure a liquefied gas material having a boiling point vtemperature at atmospheric pressure considerably below 273 K. comprising asource of supply of such liquid, a pump chamber connectedthereto having a reciprocatory element operablev in .said chamber; means for introducing liquid from said source into said chamber during the suction stroke, and positively operated suction means forv removing from said chamber prior to the deliverystroke of said plungera substantial portion of the vapor generated therein during said introduction.

17. Apparatus for delivering under pressure to a receiving means a liqueiied gas materialhaving a boiling point temperature at 'atmospheric pressure considerably below 273 K. comprising a source of supply of such liquid, a pump chamber connected thereto having a reciprocatory plunger operable Ain said chamber, the latter beingjconstructed to provide a clearance space,

`means for introducing liquid from said source into saidV chamber during lthe suction stroke,

means for removing Afrom said chamber a substantial portion of the vaporv generated therein during 'said introduction prior to the delivery stroke of said plunger, and ,means operable` following the delivery stroke of said plunger and prior tothe introduction of liquid into said chamber for withdrawing a portion of the residual gas Vvmaterial in saidchamber into a spacehaving a ,pressure below that of said receiving means.

, 18. `Apparatus for delivering under pressure a liquefied gas materialhaving a boiling point temperature at atmospheric pressure considerably .below 273 K. comprising a source of supply of vsuchliquid, a pump chamber connected thereto having a reciprocatory element operable in said chamber, means for introducing liquid from said source into said chamber during the suctionstroke, a receiving means into vwhich the liquid is discharged under elevatedpressure during the delivery stroke of said element, and means operable following the delivery stroke and'prior to the introduction of liquid into said chamber for withdrawing a portion of the residual gas material in said chamber into a space having a pressure below that of said receiving means.

, 519. The method of pumping a volatile liquid having a boiling point temperature materially below 273 K; at atmospheric pressure, which comprises introducingfa charge of' suoliv liquid from a source thereof into a confined space,-,ef fecting a positive displacement of the major part of the introduced liquid from said confined space against a higher pressure, at la .predetermined time immediately following such displacement momentarily reducing thepressure in said confined space by release of gas material therefrom into a space at a pressure lower than saidhigher pressure, and readmittingv said released gas Amaterial to said confined space at a desired. instant prior to the displacement of the next` charge therefrom.

`20. The' method of pumping a Avolatile liquid material lhaving a boiling point temperature kbelow 273 K. at atmospheric pressure which comprises maintaining a supply of the -liquid to be pumped in a state corresponding substantially to its equilibrium boilingrtemperature at the supply pressure, introducing a charge of `A liquid therefrom into a confined space at a pressure not materially different from said supply pressure. supercharging said conined space byadding an additional quantity of the gas material, and effecting a positive displacement of the major part ofthe gas material. from said coniined space against a higher pressure. u Y

121. The method of pumping a volatile liquid material having `a boiling point temperature below 273 K. at atmospheric pressure which comprises maintaining a supplyof the liquidita-be .pumped in a state corresponding substantially tol its equilibrium yboiling point temperature lat the supply pressure, introducing a charge of liquid therefrom into a confined spaceat apres- ,sure not materially different-from said Vsupply pressure, eii'ecting positive displacement of the major part of the gas material from said confined space to an area at a desired relatively high pressure, and independently releasing a minor portion of said gas material from a point of Lsaid confined space at an appreciable distance from the point of introduction of said .charge to an area of lower pressure. Y I i 22. Thel method of pumping arvolatile liquid material having a boiling point temperature below 273 K. vat atmospheric pressure whichcomprises maintaining a supply of the liquid tok be pumped in a state vcorresponding substantially to its equilibrium boiling point temperature at the supply pressure, introducing a charge of liquid therefrom into a coniined space at apressure not materially different yfrom said supply pressure, eifecting positive displacement of the major part of the gasmaterial from saidcon- Ined space to an area at a desired relatively high pressure, independently releasing a minor portion of said gas material from a point'oi said confined space at an appreciable distance from the point of introductionof. said charge to an area of lower pressure, and collecting-and rreintroducing said released minor portion into said confined space.

23. A pump for highly volatile liquids comprisingv intake and discharge valves, a pump body having a cylindrical opening and a plunger re ciprocating therein, the diameter of said plunger being materially less than the internal diameter 0f said opening, packing surrounding said plunger within said body, a Working barrel in said body adjacent said valves in alignment with said opening; said packing being widely spaced fromsaid working barrel to provide a longitudinally extended annular open space between said plunger and said cylindrical opening, the construction beisV A.ing adapted to permit .a `restricted flow of' fthe ,y material being pumped' between said working barrel and said annular Espace, and means :for

refrig'erating .atleast .a :portion of saidfpumpbody surrounding isaid annular space. Y

12,4; VApparatus for Ypumping a volatileV liquid Jharing a boiling point temperature materially :'less` `than 2li-3 :at atmospheric pressure, com- Y iprisin'g ja'. 4pump Chambon: :a Jreciprocable plunger -operabiesthrough'an opening .in vone end of .said chamber vthe latter :being .constructed to vprovide j appreciable clearance betvfeen vsaid :plunger and the inner walls ofrsaid chambeiya ivalve- .controlled lliquid inlet :at "theend vof vsaid chamber n' opposite'tsaid opening, la lvalve-fc'oni'.ro'lle'd pas- -sage for li'quid dischargegrpacking :means -for -the .portionofithe plungeripassingfthrough said openi'ing, restricted .means ifor rentinggasi matenal rromthepump :chamber .at a point `an; ap-

preciable distance .from :the inlet "toward said :openingwherebyheatedgasm'ateriall may'fbe fre'- :ZAppa/.ratusffffor :pumping :a volatile liquid -having 1a boiling point temperature :materially les'slthanfll? K. lat atmospheric pressure, hcompris'i-ng La. .pump chamber, a reciprocable plunger chamber, .a1 'Nalve-.controlled liquid inlet at -the fendlfoiesaidcchamber'opposite Eto said opening,v a i Vvaluecc ntrolled passage for )liquid fdischarge,

`packing means for ithefiporti'on of Ithe-plunger 'passing through ysaid opening, and restricted -mean's :forv venting l'gas material 'from the pump m'el'iax'niber ata pointan appreciable distance 11F-rom theinlet toward f'said. opening; a iiuid .chamber i lfexndi'ng*around the. -Working portion fof said n `ffpump chamber arrangedltoisupplyliquid to 4said A`liquid-inlet; .andyrneans providing communication operable through an .opening in-one end. offsaid,`

'hetiveedsaid `renting 'means land -said -iiuid *less :than '273' K. at atmospheric .pressure, comprising the combination with a container for supplying liquid toibe pumped, of .a :pumprhaving 'apumpchamberandiasurrounding iorefchamber rmmnected to said-"container and to fsa'id pump lchamber, valve means for controlling' the adi mission :of liquid Ltesa-id .pumpschamber from -said "fore Y.chain-Eier, a.y ll'iqui'df discharge conduit :from

' said pump-chamber, ia pumping element arranged 'tof-work infsa'id pump-chamber -to displace liquid through said- -disclfiarge vvconduit, the `connections i between said container and Vfore ychamber includinga Vliquid 1conduit connected between the liquid A"spaceof lsaid container andthe rforecharnber vfor iieeding lliquid Lto the latter and a vapor conduit vrfrom lthe vupper Aportion of said fore chamber to saidv container `tofperrnit the release of vapor vto said container, `-ajndliquid 'level response' means constructedandfarranged to prevent flow vof liqui'dithrough lsaidvapor conduit Ato said container. y A Y '27. Pumping' lapparatus according to -cl'aim- 26 jinwhich said 'pumpingr'element enters through oneend of said'pump chamber and said inlet is adjacenttheother'end of said pump chamber, ythere being apacking seal between ,the pumping element and said one`-end of 'the pump chamber,

' -arestricted vent from said pump chamber 'at -a point intermediate'-between said ends, 'and means providing communication between said vent and said'fvapor conduit. Y o Y 28. Apparatus Vfor pumping Ya, volatile :liquid y 'having' a boiling point temperature materially lso lessy than 275 K; at .atmospheric `pressure, com- Vprisi-ng .the v'combination with a fcontaineniofr Y :supplying 'liquid to '.be pumped, :of .a pump' .hav-

ing .-apump chamber :withV a .Warm end, la cold end.V and a :surrounding fore `chamber, `.the Acold -endbeing within said Iforennamber, aliquidfconduitconnecting the=rliqi1id espace offsaid container V`an'dfsaid Lforel-'clframber for supplying 'liquid 'to the -fore rchamb'er, .a `.vapor ycon-duit connecting up'- per portion of said fiore chambervwithvzsaidcon- Ltainerf-for` Yventing'vapor to said/container, a valued inlet-'between `the cold end :of Athe pump chamber 4and said fore chamber, :a valved discharge fromrsaid pump chamber, afpu-mping element larranged to :workin .said pump vchan-iber 'and fdisplace liquid. through said discharge, and 'a vent from Isaid :pump fchamberlata pointintermediate".-betwe'en said Vcold and warm-rends and V'spacewziffilorn .said inlet toward'said -warm end.

"29; Apparatus for :pumping fa volatileviiquid Ehaving afboiling .point #temperature materially "less 'than 237,3 K. fat `fatniospheric pressure com- `prisin'g the @combination of a :pump chamber, :a reciprocable plunger :operable through an :opone ingin' yonefend of said. chamber, a V'valve-controlled :'liqu'i'd inlet :near the 4end .of V'said chamber Vopposite to said opening, za valved dischargerom saidfpump chamber, said ch-amber having a-working barrel portion which vthe :end of said plunger reciprocates --to :displace liquid .through said dischargesaid. working fbarrel' portion hav- 'in'g Ja 4'dian'ieter vlarger than said :plunger to ilprovideV a desired clearance, a clearance lspace .be-

YStween the Iplunger and the Jpump chamber inthe -ling chamber; the latter beingkconstructed -lto 'providea substantial-clearancebetweensaid plunger and' :the iinn'er wall :of said chamber, .a valvecontrolled fliquid inletat theV end of 4said :chamber opposite to isaid opening,- a -valve controlled L.passage .iorfliquid discharge, packing 4means afer ithe Aporltionof theiplunger passingthroughisaidl openingfsaid packingmeans being Widelyspaced `from said=workingchamber 'theintervening `space comprisinglanielongated opening through whi'chi'said `'ness aboutfsaid' plunger, 1said annular space Thaw- .plunger-extends -of a diameter :to vprovide an annular uid space v'of substantial radial 'thicklifng sufficient :communication with -said working chamber lto allow entrance of rfluid therefrom, and lmeans for cooling at least ya portion offsaid pum-pbody surrounding -said annular spacel em- `bodying'ra -fluid passage extending `around l'sai-ld portion fand means `for' passingr -a cold- 'fluid throughsai-dpassagemeans.V Y

31. Apparatus 'fforVpumping 'a highly volatile liquid ehavi-ng a boiling point temperature l`materially less than 27f3"-K. 'at atmospheric pressure,

comprising a pump bdd-y'having a working cham- -berV therein, a reciprocable plunger `vextending ltiufoi-ig'loan opening 'in said- 'pumplbody and? ihav-- ing aninnercndportion'operablein said working chamber, the latter being constructed to provide a substantial vclearance between said plunger and the inner Wall of said chamber, a valve controlled liquid inlet at the end of said chamber opposite to said opening, a valve controlled passage for liquid discharge, packing means for the portion of the plunger passing through said opening, said packing means being widely spaced from said Working chamber the intervening space comprising an elongated opening through which said plunger extends of a diameter to provide an annular fluid space of substantial radial thickness about said plunger, said annular space having sufficient communication with said Working chamber to allow entrance of fluid therefrom, and restricted means for venting gas material from the pump body at a point spaced from said inlet toward the opposite end of said pump body.

32. A pump for liquefied gases comprising a pump body including a working barrel portion, a plunger of less diameter than said barrel reciprocating therein, a packing element surrounding said plunger, and means for removing heat from said plunger, said means comprising a jacket surrounding the pumping end of said pump, and means for passing a iluid at low subatmospheric temperature through said jacket, said pump body including an elongated portion interposed between said working barrel portion and said packing and having an internal diameter larger than that of the plunger to form an enclosure of space around said plunger, said space being in suicient communication with said Working barrel to permit passage of the pumped Ilud thereinto.

33. Apparatus for pumping a volatile liquid having a boiling point temperature materially less than 273 K. at atmospheric pressure, comprising the combination with a container for supplying liquid to be pumped, of a pump having a pumping chamber and a plunger operable therein, said pump having a cold end including said pumping chamber and an outer warm end including means connected to operate said plunger, a surrounding fore chamber, the cold end being within said fore chamber and located at` a level below said warm end, a liquid conduit connecting the liquid space of said container and said fore chamber for supplying liquid to the latter, a vapor conduit connecting an upper portion of said fore chamber with said container for venting vapor to said container, a valved inlet between said fore chamber and the inner end of the pumping chamber opposite the said warm end, a valved discharge from said pumping chamber, and means for Venting gas into said fore chamber from the end of said pumping chamber opposite to and spaced from said valved inlet.

34. Apparatus for pumping a liquefied gas having a boiling point temperature materially less than 273 K. at atmospheric pressure comprising the combination with a container for holding and supplying liqueed gas to be pumped, of a pump having a pump chamber, a surrounding forechamber holding a body of the liqueed gas in which the pump chamber is immersed, means for the admission of liquid charges to said pump chamber from said forechamber, a liquid discharge conduit from said pump chamber, and a pumping element arranged to work in said pump chamber to displace liquid through said discharge conduit, at least the liquefied gas body holding portion of said forechamber being lower than said container; a liquid conduit connected between the liquid space of said container and the forechamber for feeding liquid to the latter; a vapor conduit from the upper portion of said forechamber for the release therefrom of excess vapor tending to prevent the rise of liquid in the forechamber to a predetermined liquid level; and liquid level response means associated with said vapor conduit for preventing flow of liquefied gas through said vapor conduit.

WILLIAM F. MESINGER.

REFERENCES CITED The following references are of record in the lile of this patent:

UNITED STATES PATENTS Number Name Date 814,883 Starr Mar. 13, 1906 1,413,568 Bjornstad Apr. 25, 1922 1,878,317 Picard Sept. 20, 1932 1,880,271 Palmer Oct. 4, 1932 2,145,854 Bijur Feb. 7, 1939 2,292,375 Hansen Aug. 11, 1942 2,439,957 Anderson Apr. 20, 1948 2,439,958 Anderson Apr. 20, 1948 

1. APPARATUS FOR PUMPING A VOLATILE LIQUID HAVING A BOILING POINT TEMPERATURE MATERIALLY LESS THAN 273* K. AT ATMOSPHERIC PRESSURE, COMPRISING THE COMBINATION WITH A DEVICE FOR SUPPLYING LIQUID TO BE PUMPED HAVING THEREIN SPACES FOR BOTH GAS AND LIQUID, OF A PUMP HAVING A PUMP CHAMBER IN COMMUNICATION RESPECTIVELY WITH SAID GAS AND LIQUID SPACES, VALVE MEANS FOR CLOSING SAID COMMUNICATION, A LIQUID DISCHARGE FOR SAID PUMP CHAMBER, A PLUNGER ARRANGED TO WORK IN SAID PUMP CHAMBER, THE LATTER BEING PROVIDED WITH A DESIRED CLEARANCE AND SAID PLUNGER BEING ADAPTED TO DISPLACE LIQUID THROUGH SAID DISCHARGE, MEANS FOR SUPERCHARGING THE CLEARANCE SPACE IN 